1. Field of the Invention
This invention relates in general to article handling mechanisms and more particularly to an apparatus and method for handling various articles of manufacture which are to be processed in reactor furnaces in a manner which minimizes environmental contamination of the articles.
2. Description of the Prior Art
As is well known in the electronics arts, the manufacturing of various articles, such as low temperature oxide silicone wafers, must be accomplished with extreme care to keep such articles from being damaged and possibly ruined as a result of environmental contamination, and the requirements for a clean non-contaminating manufacturing environment and process are becoming more stringent all the time.
One particular phase of the manufacturing of this type of article which is very troublesome from a contamination standpoint is the processing of the articles in reactor furnaces. Operation of reactor furnaces inherently results in a process residue being deposited on the interior walls of the furnaces and this residue will easily become airborne if disturbed, such as during loading and unloading of the articles being processed in the furnaces.
It is a common practice to load a plurality of the articles to be processed in supporting structures which are referred to in the industry as "boats", and the boats may be formed of various materials and of various configurations as dictated by the particular articles being handled and the particular process to be accomplished in the reactor furnaces. However, the boats are generally elongated structures of substantially parallelogram cross sectional configuration with multiple compartments formed therein for receiving the articles to be processed. Such boats have traditionally been provided with wheels by which they are rolled into and out of the reactor furnaces.
The prior art loading and unloading devices have traditionally included an upwardly opening semi-circular trough into which the boats are loaded. The trough is supported by a suitable framework which is hand operated to elevate the trough, and thus the boat, into alignment with a selected one of a plurality of vertically stacked reactor furnaces, into which the boat is to be loaded. When aligned, the boat is manually pushed so that it rolls from the trough into the reactor furnace. When the processing of the articles is completed, the boat is manually pulled from the reactor furnace so that it rolls therefrom back onto the trough of the prior art loading and unloading device.
The rolling of the article supporting boat into and out of the reactor furnace will disturb the reaction process residue present on the interior sidewalls of the reactor furnace as a direct result of the operation of the furnace. When so disturbed, the residue will become an airborne contaminant which can damage, and sometimes completely ruin, the articles being processed. This prior art boat loading and unloading device has been used for sometime, but is no longer acceptable due to the increasingly stringent requirement for a clean and non-contaminating manufacturing environment and the processes associated therewith. The first problem with the prior art loading and unloading device is the above described rolling insertion into, and subsequent extraction of the boats from the reactor furnace which inherently creates an unacceptable amount of environmental contamination. The second problem results from the required manual operation of the article handling device per se, and the manual pushing and pulling of the boat. The loading area immediately in front of the reactor furnace is a very uncomfortable place for anyone to work in due to high operating temperatures of the reactor furnaces which must be open during loading and unloading operations. The natural tendency is for a worker to hurry through the trough alignment operation as well as the pushing to load and pulling to unload operations so that he can leave the extremely hot loading area. Hurried accomplishment of these operations can produce extremely aggravated environmental contamination resulting from misalignment of the trough relative to the reactor furnace, and there is very little margin for misalignment errors in that very little clearance exists between the boat and the interior sidewalls of the furnace. And, if the boat is not carefully pushed straight into or pulled straight out of the reactor furnace, the boat can assume a skewed attitude causing the wheels to skid rather than roll along the interior surfaces of the reactor furnaces.
Therefore, a need exists for a new and improved article handling apparatus and method which overcomes some of the problems and shortcomings of the prior art.